Network of brokers: problem with duplex="false" for static bridges

[jochenw <jo...@googlemail.com>]

Hello,

I have a configuration where one broker builds network connections to other
brokers. Some of the queues have to be two-way (duplex="true") and some have
to be one-way (duplex="false"). For the network connector configuration, see
below. The ActiveMQ version is 5.14.5.

The goal is that queue1 and topic1 are visible in all brokers, since the
consumer is connected to broker1, the producers to broker2 and broker3. For
the queues with the name queue2.<ID>, the producer is connected to broker1,
the consumers to broker2 or broker3. This bridge has duplex="false", because
these queues should be visible in broker1 and the broker to which the
consumer is connected, but not the other broker. E.g.: The consumer for
queue2.abc is in broker2, so this queue should only be visible in broker1
(where the producer is) and broker2, the consumer for queue2.edf is in
broker3, so this one should only be visible in broker1 and broker3.

Now the problem: when sending a message to queue2.abc, sometimes it arrives
at broker2 and is correctly consumerd there. But sometimes the message
arrives at broker3, and the Web console of broker3 shows that queue2.abc is
created there and a message enqueued. Although the queue has zero consumers,
after few seconds it is consumed from there, but nothing else happens.
Possibly, the message goes to broker2 (where it originally was meant to go),
but then dies due to networkTTL="3".

When I used a dynamic bridge and dynamicallyIncludedDestinations and
activate the advisorySupport for all involved brokers, all works correctly.

So the question is whether with static bridges, the duplex="false" clause
should work. With this, queue2.abc should never be synced to broker3, but
obviously the messages appear at broker3 anyways.

Regards,
Jochen


Network connector configuration snippet from activemq.xml of broker1 (for
the test configuration, all brokers are running on the same host in docker
containers with 61616 mapped to different ports):

<networkConnectors>
    <networkConnector
uri="static:(failover:(tcp://myhost:62616)?maxReconnectAttempts=0)"
                        name="broker1_broker2_duplex"
        duplex="true"
        networkTTL="3"
        staticBridge="true">
        <staticallyIncludedDestinations>
            <queue physicalName="queue1"/>
            <topic physicalName="topic1"/>
        </staticallyIncludedDestinations>
    </networkConnector>
    
    <networkConnector
uri="static:(failover:(tcp://myhost:62616)?maxReconnectAttempts=0)"
                        name="broker1_broker2_simplex"
        duplex="false"
        networkTTL="3"
        staticBridge="true">
        <staticallyIncludedDestinations>
                <queue physicalName="queue2.>"/>
        </staticallyIncludedDestinations>
    </networkConnector>

    <networkConnector
uri="static:(failover:(tcp://myhost:63616)?maxReconnectAttempts=0)"
                        name="broker1_broker3_duplex"
        duplex="true"
        networkTTL="3"
        staticBridge="true">
        <staticallyIncludedDestinations>
            <queue physicalName="queue1"/>
            <topic physicalName="topic1"/>
        </staticallyIncludedDestinations>
    </networkConnector>
    
    <networkConnector
uri="static:(failover:(tcp://myhost:63616)?maxReconnectAttempts=0)"
                        name="broker1_broker3_simplex"
        duplex="false"
        networkTTL="3"
        staticBridge="true">
        <staticallyIncludedDestinations>
                <queue physicalName="queue2.>"/>
        </staticallyIncludedDestinations>
    </networkConnector>
</networkConnectors>






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Re: Network of brokers: problem with duplex="false" for static bridges

[jochenw <jo...@googlemail.com>]

Hi Tim,

thanks for clarifying this. I may have expressed it not precisely in my
answer: the problem exactly was that for the broker1_broker2_simplex bridge,
when sending messages to a queue which is initially only known by broker 2
(because only there a consumer exists for this queue), sometimes doesn't go
1 -> 2, but goes 1 -> 3. Which is clear, since for a static bridge, broker 1
doesn't know which broker has the consumer, and since the includes conatin a
wildcard, it will just use round robin to send the messages to the connected
brokers.

So it's not about the duplex=false, but it's about the static bridge. When
using dynamic bridges as proposed, everything works fine.

Regards,
Jochen



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Re: Network of brokers: problem with duplex="false" for static bridges

[Tim Bain <tb...@alumni.duke.edu>]

You've misunderstood the duplex setting. Setting the 1-2 link as simplex
from the 1 side means that messages can go from 1 to 2 but not from 2 to 1
(unless you define a reciprocal connection in the 2 broker, but we're not
considering that case here). It has nothing to do with applying a condition
(consumer is present) to whether messages should be forwarded from 1 to 2,
and therefore nothing is being overridden.

But Jakub is exactly right about the correct way to get the behavior you
want.

Tim

On Jun 29, 2017 1:24 AM, "jochenw" <jo...@googlemail.com> wrote:

> Hi Jakub,
>
> thanks for the explanation! I was not aware that this even overrides the
> duplex="false" setting. But thinking about it again, it makes sense, since
> the duplex setting is relevant for the sync direction of consumers, not for
> the push direction / filtering of messages.
>
> So no other way than using dynamic bridges, at least for the one-way
> network
> connectors.
>
> Regards,
> Jochen
>
>
>
> --
> View this message in context: http://activemq.2283324.n4.
> nabble.com/Network-of-brokers-problem-with-duplex-false-for-
> static-bridges-tp4727986p4728049.html
> Sent from the ActiveMQ - User mailing list archive at Nabble.com.
>

Re: Network of brokers: problem with duplex="false" for static bridges

[jochenw <jo...@googlemail.com>]

Hi Jakub,

thanks for the explanation! I was not aware that this even overrides the
duplex="false" setting. But thinking about it again, it makes sense, since
the duplex setting is relevant for the sync direction of consumers, not for
the push direction / filtering of messages.

So no other way than using dynamic bridges, at least for the one-way network
connectors.

Regards,
Jochen



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